In brachytherapy, and especially in in vivo brachytherapy, a radiation source (being an example of an energy provision source) is placed within the body at a position within or next to a tissue requiring radiation treatment. Several forms of cancer, such as prostate cancer, are treated with brachytherapy. In these forms of treatment it is important that the radiation source is placed at a predetermined position within the body to obtain the most effective treatment of the cancerous tissue. Before starting the treatment, a treatment plan is made which defines at which positions in or near the treated organ the radiation source(s) must be placed.
Also in other forms of therapy an energy emitting source is guided through a probe, needle, trocar or, for example, a catheter into the body. In these forms of therapy it is also required to know the exact position of an energy emitting source within the body. An example of such therapeutic technique is laser induced thermal therapy wherein an optical fiber is inserted through a probe into a tumor and laser light is guided to the tip of the optical fiber.
As indicated by the presentation of Berkeley University, as available on website address http://automation.berkeley.edu/projects/needlesteering/Brachy.swf (consulted on Aug. 29, 2013), in brachytherapy a treatment plan is made with help of software which estimates the cumulative effect of the radiation dose clouds that will be produced by each radiation source. The presentation further shows how the radiation sources are inserted into the treated organ and that, during providing the radiation sources to the tissue, ultrasound equipment is used to visualize the treated organ. The presentation also discloses that the doctor who inserts needles for placing the radiation source is guided by the ultrasound display when inserting the needles in the treated organ. Thus, based on one or more subsequent images, the doctor is able to see where the needle is within the treated organ. It is known that needle placement on basis of the above procedure does not necessarily result in an accurate placement of the radiation sources. In such procedures the person who places the radiation sources does not receive enough quality feedback which, as also presented in the presentation, results in sub-optimal results.